Duo-Servo Brakes adjust how?

Duo-Servo brakes are a specific type of drum brake system commonly found in vehicles. They are designed to enhance braking efficiency by utilizing the natural motion of the wheel. When the brakes are applied, the leading shoe engages first due to the rotation of the drum. As the vehicle moves, this action effectively pulls the secondary shoe into contact with the drum as well.

The adjustment mechanism of Duo-Servo brakes is particularly optimized for operation when applying the brakes in reverse. In this scenario, the leading shoe will be the one that moves in the direction of the motion when the vehicle is backing up, which helps to self-adjust and reinforce the brake shoe positions. The design ensures that when reverse braking occurs, the shoes get tighter and compensate for wear, maintaining effective braking performance.

Unlike other conditions, such as when applying brakes in forward motion or engaging the parking brake, the unique self-adjusting mechanism of Duo-Servo brakes primarily comes into play during reverse operation. Therefore, this context highlights why the option regarding applying the brakes in reverse is accurate in describing how Duo-Servo brakes adjust.